David is correct with the bolt configuration. If you’re not using the original bolts and relying on off the self replacement, then there is a chance that the paint will get damaged when tightening. If its a Nut and Bolt fixture, make sure you hold the bolt still and turn the nut where possible. When I have no alternative, other than to use current manufactured bolts, I set up and modify a swag of bolts to have the small raised circular section under the head of the bolt.
Often in a restoration of an E Type, particularly when the paint is being done by someone that is not a regular restorer of E Types, they do too good a job of painting the engine frames, picture frame and the area of the bulk head where the engine frames attach. By the time these components have the various coats of primer and then top coat, the accumulated film thickness of the paint in the areas where two surfaces interface, is considerable. In essence, you have a shim made of paint between these surfaces that will definitely change over time.
Should your parts compare with the above scenario, either carefully thin out the paint thickness in these areas before assembly, or failing that, re-tighten all these interface bolts on a regular basis for the first year or so; a longer period if the car doesn’t get driven much.
I believe it was Nick Saltarelli that posted that the less organic material you can have on the car the better and I concur with that; its one of those cases where less is more.